NEETZoologyHuman Reproduction
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The zona pellucida layer of the ovum ensures that only one sperm can fertilise an ovum. Reason (R): Contact of a sperm with the zona pellucida induces changes in the membrane that block the entry of additional sperms. In the light of the above statements, choose the most appropriate answer from the
Options
- ABoth (A) and (R) are true and (R) is the correct explanation of (A)
- BBoth (A) and (R) are true but (R) is not the correct explanation of (A)
- C(A) is true but (R) is false
- D(A) is false but (R) is true
Correct answer
A. Both (A) and (R) are true and (R) is the correct explanation of (A)
Step-by-step solution
During fertilisation, a sperm comes in contact with the zona pellucida layer of the ovum. This contact induces changes in the membrane that block the entry of additional sperms. This mechanism is crucial as it prevents polyspermy, ensuring that only one sperm can fertilise an ovum. Therefore, both Assertion (A) and Reason (R) are true, and Reason (R) correctly explains how the zona pellucida ensures monospermy as stated in Assertion (A). Answer: Both (A) and (R) are true and (R) is the correct explanation of (A)